Bilayered metal hardmasks for use in Dual Damascene etch schemes

Abstract

A metal hardmask for use with a Dual Damascene process used in the manufacturing of semiconductor devices. The metal hardmask has advantageous translucent characteristics to facilitate alignment between levels while fabricating a semiconductor device and avoids the formation of metal oxide residue deposits. The metal hardmask comprises a first or primary layer of TiN (titanium nitride) and a second or capping layer of TaN (tantalum nitride).

1. A metal hardmask for providing a template for patterning a dielectric stack comprising:
 an unetched dielectric stack to be patterned; and 
 a patterned bi-layer metal hardmask covering said unetched dielectric stack, both layers of said patterned bi-layer metal hardmask having the same selected pattern and comprising:
 a layer of TiN (titanium nitride), and 
 a layer of TaN (tantalum nitride) capping said patterned layer of TiN, said capping layer of TaN also having said selected pattern such that both layers of said bi-layer metal hardmask mask the same portion of said dielectric stack. 
 
 
     
     
       2. The metal hardmask of  claim 1  wherein said dielectric stack includes a layer of organic dielectric and a layer of SiO 2  (silicon dioxide). 
     
     
       3. The metal hardmask of  claim 2  wherein said layer of organic dielectric material has a thickness of between about 0.1 μm and about 0.5 μm. 
     
     
       4. The metal hardmask of  claim 1  wherein said layer of organic dielectric has a thickness of between about 0.2 and 0.26 μm and is a low-k dielectric aromatic polymer resin. 
     
     
       5. The metal hardmask of  claim 1  wherein said layer of organic dielectric has a thickness of between about 0.4 and 0.46 μm and is a low-k dielectric aromatic polymer resin. 
     
     
       6. The metal hardmask of  claim 3  wherein said layer of SiO 2  has a thickness of between about 0.1 μm and about 0.3 μm. 
     
     
       7. The metal hardmask of  claim 2  wherein said layer of SiO 2  has a thickness of between about 0.1 μm and about 0.3 μm. 
     
     
       8. The metal hardmask of  claim 1  further comprising at least one layer of etch stop material between said dielectric stack and said patterned layer of TiN. 
     
     
       9. The metal hardmask of  claim 8  wherein said at least one layer of etch stop material comprises a layer of a low dielectric copper barrier and a layer of SiN 2  (silicon nitride). 
     
     
       10. The metal hardmask of  claim 9  wherein said layer of low dielectric copper barrier is a low silicon carbide based film. 
     
     
       11. The metal hardmask of  claim 1  wherein said layer of TiN is between about 20 nm and about 25 nm in thickness. 
     
     
       12. The metal hardmask of  claim 11  wherein said layer of TaN is between about 7.5 nm and about 10 nm in thickness. 
     
     
       13. The metal hardmask of  claim 1  wherein said layer of TaN is between about 7.5 nm and about 10 nm in thickness. 
     
     
       14. The metal hardmask of  claim 1  further comprising a first structure including at least one level of metallization and wherein said dielectric stack covers said first structure. 
     
     
       15. The metal hardmask of  claim 14  wherein said level of metallization comprises copper metallization.